sessionsandsubscriptionsdb.cpp
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/*
This file is part of FlashMQ (https://www.flashmq.org)
Copyright (C) 2021 Wiebe Cazemier
FlashMQ is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as
published by the Free Software Foundation, version 3.
FlashMQ is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public
License along with FlashMQ. If not, see <https://www.gnu.org/licenses/>.
*/
#include "sessionsandsubscriptionsdb.h"
#include "mqttpacket.h"
#include "threadglobals.h"
#include "cassert"
SubscriptionForSerializing::SubscriptionForSerializing(const std::string &clientId, char qos) :
clientId(clientId),
qos(qos)
{
}
SubscriptionForSerializing::SubscriptionForSerializing(const std::string &&clientId, char qos) :
clientId(clientId),
qos(qos)
{
}
SessionsAndSubscriptionsDB::SessionsAndSubscriptionsDB(const std::string &filePath) : PersistenceFile(filePath)
{
}
void SessionsAndSubscriptionsDB::openWrite()
{
PersistenceFile::openWrite(MAGIC_STRING_SESSION_FILE_V2);
}
void SessionsAndSubscriptionsDB::openRead()
{
PersistenceFile::openRead();
if (detectedVersionString == MAGIC_STRING_SESSION_FILE_V1)
readVersion = ReadVersion::v1;
else if (detectedVersionString == MAGIC_STRING_SESSION_FILE_V2)
readVersion = ReadVersion::v2;
else
throw std::runtime_error("Unknown file version.");
}
SessionsAndSubscriptionsResult SessionsAndSubscriptionsDB::readDataV2()
{
const Settings *settings = ThreadGlobals::getSettings();
SessionsAndSubscriptionsResult result;
while (!feof(f))
{
bool eofFound = false;
const int64_t fileSavedAt = readInt64(eofFound);
if (eofFound)
continue;
const int64_t now_epoch = std::chrono::duration_cast<std::chrono::seconds>(std::chrono::system_clock::now().time_since_epoch()).count();
const int64_t persistence_state_age = fileSavedAt > now_epoch ? 0 : now_epoch - fileSavedAt;
logger->logf(LOG_DEBUG, "Session file was saved at %ld. That's %ld seconds ago.", fileSavedAt, persistence_state_age);
const uint32_t nrOfSessions = readUint32(eofFound);
if (eofFound)
continue;
std::vector<char> reserved(RESERVED_SPACE_SESSIONS_DB_V2);
CirBuf cirbuf(1024);
// TODO: all that settings and thread data needs to be removed from Client.
std::shared_ptr<ThreadData> dummyThreadData;
std::shared_ptr<Settings> dummySettings(new Settings()); // TODO: this is wrong: these are not from config file
std::shared_ptr<Client> dummyClient(new Client(0, dummyThreadData, nullptr, false, nullptr, dummySettings, false));
for (uint32_t i = 0; i < nrOfSessions; i++)
{
readCheck(buf.data(), 1, RESERVED_SPACE_SESSIONS_DB_V2, f);
uint32_t usernameLength = readUint32(eofFound);
readCheck(buf.data(), 1, usernameLength, f);
std::string username(buf.data(), usernameLength);
uint32_t clientIdLength = readUint32(eofFound);
readCheck(buf.data(), 1, clientIdLength, f);
std::string clientId(buf.data(), clientIdLength);
std::shared_ptr<Session> ses = std::make_shared<Session>();
result.sessions.push_back(ses);
ses->username = username;
ses->client_id = clientId;
logger->logf(LOG_DEBUG, "Loading session '%s'.", ses->getClientId().c_str());
const uint32_t nrOfQueuedQoSPackets = readUint32(eofFound);
for (uint32_t i = 0; i < nrOfQueuedQoSPackets; i++)
{
const uint16_t id = readUint16(eofFound);
const uint32_t packlen = readUint32(eofFound);
assert(id > 0);
cirbuf.reset();
cirbuf.ensureFreeSpace(packlen + 32);
readCheck(cirbuf.headPtr(), 1, packlen, f);
cirbuf.advanceHead(packlen);
MqttPacket pack(cirbuf, packlen, 2, dummyClient); // TODO: store the 2 in the file
pack.handlePublish(true);
Publish pub(pack.getPublishData());
logger->logf(LOG_DEBUG, "Loaded QoS %d message for topic '%s'.", pub.qos, pub.topic.c_str());
ses->qosPacketQueue.queuePublish(std::move(pub), id);
}
const uint32_t nrOfIncomingPacketIds = readUint32(eofFound);
for (uint32_t i = 0; i < nrOfIncomingPacketIds; i++)
{
uint16_t id = readUint16(eofFound);
assert(id > 0);
logger->logf(LOG_DEBUG, "Loaded incomming QoS2 message id %d.", id);
ses->incomingQoS2MessageIds.insert(id);
}
const uint32_t nrOfOutgoingPacketIds = readUint32(eofFound);
for (uint32_t i = 0; i < nrOfOutgoingPacketIds; i++)
{
uint16_t id = readUint16(eofFound);
assert(id > 0);
logger->logf(LOG_DEBUG, "Loaded outgoing QoS2 message id %d.", id);
ses->outgoingQoS2MessageIds.insert(id);
}
const uint16_t nextPacketId = readUint16(eofFound);
logger->logf(LOG_DEBUG, "Loaded next packetid %d.", ses->nextPacketId);
ses->nextPacketId = nextPacketId;
const uint32_t originalSessionExpiryInterval = readUint32(eofFound);
const uint32_t compensatedSessionExpiry = persistence_state_age > originalSessionExpiryInterval ? 0 : originalSessionExpiryInterval - persistence_state_age;
const uint32_t sessionExpiryInterval = std::min<uint32_t>(compensatedSessionExpiry, settings->getExpireSessionAfterSeconds());
const uint16_t maxQosPending = std::min<uint16_t>(readUint16(eofFound), settings->maxQosMsgPendingPerClient);
// We will set the session expiry interval as it would have had time continued. If a connection picks up session, it will update
// it with a more relevant value.
// The protocol version 5 is just dummy, to get the behavior I want.
ses->setSessionProperties(maxQosPending, sessionExpiryInterval, 0, ProtocolVersion::Mqtt5);
}
const uint32_t nrOfSubscriptions = readUint32(eofFound);
for (uint32_t i = 0; i < nrOfSubscriptions; i++)
{
const uint32_t topicLength = readUint32(eofFound);
readCheck(buf.data(), 1, topicLength, f);
const std::string topic(buf.data(), topicLength);
logger->logf(LOG_DEBUG, "Loading subscriptions to topic '%s'.", topic.c_str());
const uint32_t nrOfClientIds = readUint32(eofFound);
for (uint32_t i = 0; i < nrOfClientIds; i++)
{
const uint32_t clientIdLength = readUint32(eofFound);
readCheck(buf.data(), 1, clientIdLength, f);
const std::string clientId(buf.data(), clientIdLength);
char qos;
readCheck(&qos, 1, 1, f);
logger->logf(LOG_DEBUG, "Saving session '%s' subscription to '%s' QoS %d.", clientId.c_str(), topic.c_str(), qos);
SubscriptionForSerializing sub(std::move(clientId), qos);
result.subscriptions[topic].push_back(std::move(sub));
}
}
}
return result;
}
void SessionsAndSubscriptionsDB::writeRowHeader()
{
}
void SessionsAndSubscriptionsDB::saveData(const std::vector<std::unique_ptr<Session>> &sessions, const std::unordered_map<std::string, std::list<SubscriptionForSerializing>> &subscriptions)
{
if (!f)
return;
char reserved[RESERVED_SPACE_SESSIONS_DB_V2];
std::memset(reserved, 0, RESERVED_SPACE_SESSIONS_DB_V2);
const int64_t now_epoch = std::chrono::duration_cast<std::chrono::seconds>(std::chrono::system_clock::now().time_since_epoch()).count();
logger->logf(LOG_DEBUG, "Saving current time stamp %ld", now_epoch);
writeInt64(now_epoch);
writeUint32(sessions.size());
CirBuf cirbuf(1024);
for (const std::unique_ptr<Session> &ses : sessions)
{
logger->logf(LOG_DEBUG, "Saving session '%s'.", ses->getClientId().c_str());
writeRowHeader();
writeCheck(reserved, 1, RESERVED_SPACE_SESSIONS_DB_V2, f);
writeUint32(ses->username.length());
writeCheck(ses->username.c_str(), 1, ses->username.length(), f);
writeUint32(ses->client_id.length());
writeCheck(ses->client_id.c_str(), 1, ses->client_id.length(), f);
const size_t qosPacketsExpected = ses->qosPacketQueue.size();
size_t qosPacketsCounted = 0;
writeUint32(qosPacketsExpected);
for (const QueuedPublish &p: ses->qosPacketQueue)
{
qosPacketsCounted++;
const Publish &pub = p.getPublish();
assert(!pub.splitTopic);
assert(pub.topicAlias == 0);
logger->logf(LOG_DEBUG, "Saving QoS %d message for topic '%s'.", pub.qos, pub.topic.c_str());
const MqttPacket pack(ProtocolVersion::Mqtt5, pub);
const uint32_t packSize = pack.getSizeIncludingNonPresentHeader();
cirbuf.reset();
cirbuf.ensureFreeSpace(packSize + 32);
pack.readIntoBuf(cirbuf);
writeUint16(p.getPacketId());
writeUint32(packSize);
writeCheck(cirbuf.tailPtr(), 1, cirbuf.usedBytes(), f);
}
assert(qosPacketsExpected == qosPacketsCounted);
writeUint32(ses->incomingQoS2MessageIds.size());
for (uint16_t id : ses->incomingQoS2MessageIds)
{
logger->logf(LOG_DEBUG, "Writing incomming QoS2 message id %d.", id);
writeUint16(id);
}
writeUint32(ses->outgoingQoS2MessageIds.size());
for (uint16_t id : ses->outgoingQoS2MessageIds)
{
logger->logf(LOG_DEBUG, "Writing outgoing QoS2 message id %d.", id);
writeUint16(id);
}
logger->logf(LOG_DEBUG, "Writing next packetid %d.", ses->nextPacketId);
writeUint16(ses->nextPacketId);
writeUint32(ses->sessionExpiryInterval);
writeUint16(ses->maxQosMsgPending);
}
writeUint32(subscriptions.size());
for (auto &pair : subscriptions)
{
const std::string &topic = pair.first;
const std::list<SubscriptionForSerializing> &subscriptions = pair.second;
logger->logf(LOG_DEBUG, "Writing subscriptions to topic '%s'.", topic.c_str());
writeUint32(topic.size());
writeCheck(topic.c_str(), 1, topic.size(), f);
writeUint32(subscriptions.size());
for (const SubscriptionForSerializing &subscription : subscriptions)
{
logger->logf(LOG_DEBUG, "Saving session '%s' subscription to '%s' QoS %d.", subscription.clientId.c_str(), topic.c_str(), subscription.qos);
writeUint32(subscription.clientId.size());
writeCheck(subscription.clientId.c_str(), 1, subscription.clientId.size(), f);
writeCheck(&subscription.qos, 1, 1, f);
}
}
fflush(f);
}
SessionsAndSubscriptionsResult SessionsAndSubscriptionsDB::readData()
{
SessionsAndSubscriptionsResult defaultResult;
if (!f)
return defaultResult;
if (readVersion == ReadVersion::v1)
logger->logf(LOG_WARNING, "File '%s' is version 1, an internal development version that was never finalized. Not reading.", getFilePath().c_str());
if (readVersion == ReadVersion::v2)
return readDataV2();
return defaultResult;
}